Memory cards essentially comprise a memory module and a card body which is generally made of a plastic material. Electronic memory cards have a memory module in the form of an electronics module essentially constituted by a semiconductor chip having an integrated circuit formed therein and a piece of printed circuit on which the chip is fixed and which also defines external electrical contact tabs. The electronics module is fixed in the card body in such a manner as to ensure that the electrical contact tabs lie flush with one of the main faces of the card body.
The card body is in the form of a rectangular parallel-piped which must be less than 1 mm thick and which is as defined by international standard ISO 7810. The edges of the card body are used as a reference for positioning the card in a card reader so that the contact tabs on the card come into electrical contact with a connector in the card reader.
It should be added that the card body also satisfies other specifications relating to the quality of its surface state and to well-defined bending behaviour: in torsion; in the longitudinal direction of the card body; and in the transverse direction. These specifications are defined by the above-specified ISO standard. In addition, the card body must not encourage electrostatic charge retention.
In order to solve this problem, French patent application number 8700446, published on July 22, 1988 has already proposed manufacturing a card by an injection molding method comprising the following stages:
a memory module is provided having an access face and at least one anchor element; PA1 said module is placed in a mold and it is held in place in such a manner as to dispose the access face of the memory module against one of the walls of the mold; PA1 a plastic material is inserted into the mold in such a manner as to cause the entire volume delimited by the walls of the mold and not occupied by said memory module to be occupied by the plastic material; and PA1 the part made in this way is then unmolded. PA1 providing a mold whose mold cavity defines the outside shape of said card; PA1 providing a support element; PA1 providing a memory module having an access face; PA1 fixing the access face of said memory module to one of the faces of the support element; PA1 placing said support element in said mold in such a manner as to ensure that its periphery is fixed to said mold; PA1 injecting a plastic material into said mold so that the plastic material fills said mold cavity and so that said memory module is embedded in the plastic material; and PA1 unmolding the part obtained in this way and separating the support element from said part, thereby causing said memory module to be inserted in the card body with said access face of the memory module being disposed in said first main face of the card body.
Another problem which arises in manufacturing memory cards is providing graphics elements as generally required on at least one of the main faces of the card body, said graphics elements being constituted, for example, by alphanumeric information or by drawings for decorative purposes.
When the graphics element is quite complicated either because of the shape of its outline or else because of the shades of color to be obtained, the stage during which the pattern is printed e.g. by silkscreen printing or by offset printing can lead to failure, particularly if very strict quality standards are required concerning the outline and the colors. In the event of failure, cards having printing which is not up to standard must be rejected. This entails a loss of manufacturing costs involving raw materials, components, and manufacturing operations up to and including the stage during which the unacceptable printing is performed. These costs are particularly high if the pattern is made after the electronics module has already been implanted in the card body. This situation applies particularly, but not exclusively, to the case where a card is manufactured by molding the card body directly over the electronics module using the technique described in above-mentioned French patent application number 8700446.
In order to remedy these drawbacks, an object of the invention is to provide a method of manufacturing a card, in particular a memory card, in which the stage during which the pattern is provided on the card body cannot of itself give rise to a card being rejected.
An object of the invention is to provide a way of manufacturing a memory card, in particular an electronics memory card, in which the card body is molded over the memory module, but in which graphics elements can be provided on the card body, if so desired, under economic conditions which are particularly advantageous.